Other prominent supporters include Stanford physicist Charles Munger Jr., the son of billionaire Berkshire Hathaway Inc. Vice Chairman Charles Munger, who has donated more than $10 million, and former Univision chief executive Jerry Perenchio, a frequent Republican donor, who has given $800,000.Some of the contributions have been mysterious. The Fair Political Practices Commission filed a successful lawsuit seeking the records of the Phoenix-based Americans for Responsible Leadership after the group made an $11 million contribution to the Small Business Action Committee PAC. The political action committee is supporting a dual campaign to pass Proposition 32 and defeat Gov. Jerry Brown's November tax initiative. The lawsuit revealed that a secondary group, again with ties to the Koch brothers, was behind some of the out-of-state money. Across the country, government workers have been facing political pressure to roll back pension and retiree health care benefits that in many cases are much more generous than those received by their private-sector counterparts and are straining state and municipal budgets. Indiana Gov. Mitch Daniels signed a right-to-work law in February banning unions from collecting mandatory fees for representation, and labor suffered a defeat in Wisconsin earlier this year when Republican Gov. Scott Walker defeated a recall challenge following his push to limit collective bargaining rights for most public workers. Even without Proposition 32, California has put unions on the defensive, as well. In June, voters in San Diego and San Jose overwhelmingly approved reduced retirement benefits for city workers. This fall, Gov. Jerry Brown persuaded Democratic lawmakers to pass pension reductions that will apply to new state and local government workers.